Geant4DNA Simulation for the absorbed energy in water of electrons with energy below 1keV

Dear Experts,
I have recently used Geant4V11.01 to simulation the dose-point kernel (DPK) based on TestEM12 example. The chosen physics_list were G4EmDNAPhysics_option2/4/6, respectively. The primary beam was a point source of electrons located in a sphere of water.
Here’s the shape of DPK for electrons of 50 eV:

The DPK shape is fine for the case of 1 keV electron. However, for 50 eV, the DPK has a strange shapes when radius go near to 0 as in the attached figure (close to the origin of the point source). This can be seen also with 100 eV, 500 eV,… 800 keV electrons.

Would you please help me point out what happens with the absorbed energy calculated by G4EmDNAPhysics_option2/4/6 below 1keV?

Thank you very much,
Best Regards,